Patients with axial spondyloarthritis (axSpA) can be divided into clinical subgroups with remarkably dissimilar health statuses based on gender, physician global assessment of disease activity (PGDA), and pain area, according to a study published in Arthritis Research & Therapy.
Patients with axSpA recruited from the outpatient clinic for SpA at the University Hospitals of Leuven in Belgium (n=170) were included in this cross-sectional observational study. Researchers sought to increase knowledge regarding pain areas and gender differences in axSpA, and to determine how these relate to disease activity and clinical outcomes.
Anterior and posterior body charts were used to determine the presence or absence of peripheral articular, peripheral nonarticular, and axial pain in 108 men and 62 women. Gender comparisons were made using multivariate odds ratios (ORs). Four subgroups were classified by physician global assessment of disease activity (PGDA) and widespread nonarticular pain (P <.05).
The clinical differences between subgroups were explored using general linear models, including the Hospital Anxiety and Depression Scale (subscale depression [HADS-D] and subscale anxiety [HADS-A]) to measure anxiety, the 11-item version of the Tampa Scale for Kinesiophobia (TSK-11) to determine fear of movement, the Bath Ankylosing Spondylitis Functional Index (BASFI) to measure activity limitations, and the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) to measure disease activity. Further gender comparisons were made using principal component analysis (PCA) to delineate differences in disease activity structure.
Cervicothoracic, cervical, and lumbar pain was prevalent in 47.6%, 47.6%, and 74.4% of participants, respectively. Although axial thoracic pain was the least common (32.4%), it was approximately 3 times more likely in women (OR, 2.92; P =.009). Women were also 2 to 3 times more likely to experience peripheral articular pain (OR, 2.34; P=.023) and widespread axial pain (OR, 3.33; P =.007), and 2.5 times more likely to experience axial cervicothoracic junction pain (OR, 2.48; P =.018).
Overall, 27% of patients fell into a subgroup of nonarticular peripheral pain combined with low PGDA that was associated with worse HADS-A and TSK-11 in women and worse HADS-D, HADS-A, BASDAI, and BASFI in men (P <.05). Researchers observed a 2-factor structure for disease activity outcomes in the women participating in the study, but not in the men.
Study investigators conclude that “women more frequently exhibited [thoracic] and [cervicothoracic junction] pain with a wider lateral spread, regardless of disease status. Our finding of widespread (non-articular) peripheral pain in combination with low PGDA questions current clinical decision-making using disease activity measures in a subgroup of axSpA. Also, the [2-factor] structure of disease activity found in women should be considered in the development of outcome instruments in axSpA.”
This study was supported by the Division of Rheumatology, University Hospitals Leuven, and Fonds voor Wetenschappelijk Reuma Onderzoek, Brussels.
Swinnen TW, Westhovens R, Dankaerts W, de Vlam K. Widespread pain in axial spondyloarthritis: clinical importance and gender differences [published online July 27, 2018]. Arthritis Res Ther. doi: 10.1186/s13075-018-1626-8